The cutting of gems such as diamonds is a highly skilled art with many variables that combine to create gems of varying qualities. The laws of physics dictate that, when proportioned correctly, a diamond will reflect back a maximum amount of the light that enters the stone. Because proportions are such a critical element in the diamond's beauty, the ideal cut has become identified as the standard of diamond beauty. In this regard FIG. 1 illustrates the various parameters that define the cut of a diamond, including table, crown and pavilion angles, culet and girdle.
Most of a diamond's life and sparkle comes from its cut. Diamonds are often cut to retain weight, which results in light leaking out the back of the diamond, and also a dull drab diamond with a smaller diameter.
In 1919, Marcel Tolkowsky wrote a Masters thesis on the ideal proportions for round diamonds. The proportions designated by Tolkowsky's have generally been considered as well chosen and have been the benchmark in the industry for the past 80 years. The target set by Tolkowsky was of a diamond with crown angle of 34.5°, pavilion 40.75° and table of 53%.
However, Tolkowsky's ideal design has led to the industry developing the have been used to develop tolerances of an “ideal cut”. This has been an incorrect application of Tolkowsky's ideal, as not all diamonds within the designated tolerances in fact could be described as “ideal”. Further, recent research has shown that there are diamonds outside of the proportions indicated by Tolkowsky that are equally or even more beautiful.
Cut grading systems were developed in order to assist in classifying high quality cuts from lesser quality cuts. However, as existing cut grading systems are generally based on the developed tolerances, they are inadequate. Further such systems are feature oriented in that they provide a numerical grading for the diamond. Laboratories that provide such a numerical grading take the worst scoring feature and assign that score as a cut grade. This process ignores the complex interrelationship of facets as light reflects and refracts on its passage through a diamond. A diamond with a slight deviation on each of these measures can rate as ideal even though the performance is only fair. Equally some deviations for Tolkowsky's proportions can compensate for other undesirable deviations in other factors.
It is therefore apparent that large discrepancies can exist in the way institutional “tolerances” are applied to a single “ideal cut”. Further, today's grading systems are not flexible enough to take account of different proportion preferences of individuals or geographic markets. Many consumers, particularly sophisticated consumers, expect more of cut grading systems. There is therefore a need for a more flexible and accurate grading system.
It is also apparent that there are many variables in assessing the quality and beauty of a diamond, and that, particularly from the lay person's point of view, it can be a difficult decision choosing the right diamond. There is therefore a need for a simplified gem assessment system and method.
In addition, there are numerous diamond traders around the world selling diamonds of varying quality. For a person, particularly one not experienced in the gem trade, it can be a difficult process evaluating diamonds and judging their appearance based upon the cut factors listed by the traders. Also, it can be time-consuming process evaluating diamonds from the various traders.
There is therefore also a need for an improved system for evaluating gems of multiple remote traders.
The present invention seeks to overcome or alleviate at least one of the problems of the prior art.